344 BOOK VIII. 



through which there flows on to the iron plate so much water as is necessary 

 for this washing. Next, a boy throws the metalliferous material on to the 

 iron plate with an iron shovel and breaks the small lumps, stirring them this 

 way and that with the same implement. Then the water and sand penetra- 

 ting the holes of the plate, fall into the box, while all the coarse gravel remains 

 on the plate, and this he throws into a wheelbarrow with the same shovel. 

 Meantime, a younger boy continually stirs the sand under the plate with a 

 wooden scrubber nearly as wide as the box, and drives it to the upper end of 

 the box ; the lighter material, as well as a small amount of tin-stone, is 

 carried by the water down into the underlying trough. The boys carry on 

 this labour without intermission until they have filled four wheelbarrows 

 with the coarse and worthless residues, which they carry off and throw away, or 

 three wheelbarrows if the material is rich in black tin. Then the foreman 

 has the plank removed which was in front of the iron plate, and on which the 

 boy stood. The sand, mixed with the tin-stone, is frequently pushed backward 

 and forward with a scrubber, and the same sand, because it is lighter, takes 

 the upper place, and is removed as soon as it appears ; that which takes the 

 lower place is turned over with a spade, in order that any that is light 

 can flow away ; when all the tin-stone is heaped together, he shovels it out 

 of the box and carries it away. While the foreman does this, one boy with 

 an iron hoe stirs the sand mixed with fine tin-stone, which has run out of the 

 box and has settled in the trough and pushes it back to the uppermost part 

 of the trough, and this material, since it contains a very great amount of tin- 

 stone, is thrown on to the plate and washed again. The material which has 

 settled in the lowest part of the trough is taken out separately and piled in a 

 heap, and is washed on the ordinary strake ; that which has settled in the 

 pool is washed on the canvas strake. In the summer-time this fruitful 

 labour is repeated more often, in fact ten or eleven times. The tin-stone 

 which the foreman removes from the box, is afterward washed in a jigging 

 sieve, and lastly in a tub, where at length all the sand is separated out. 

 Finally, any material in which are mixed particles of other metals, can be 

 washed by all these methods, whether it has been disintegrated from veins or 

 stringers, or whether it originated from venae dilatatae, or from streams and 

 rivers. 



The sixth method of washing material of this kind is even more modern 

 and more useful than the last. Two boxes are constructed, into each of 

 which water flows through spouts from a cross trough into which it has been 

 discharged through a pipe or launder. When the material has been agitated 

 and broken up with iron shovels by two boys, part of it runs down and falls 

 through the iron plates full of holes, or through the iron grating, and flows 

 out of the box over a sloping surface into another cross trough, and from 

 this into a strake seven feet long and two and a half feet wide. Then 

 the foreman again stirs it with a wooden scrubber that it may become 

 clean. As for the material which has flowed down with the water and settled 

 in the third cross trough, or in the launder which leads from it, a third boy 

 rakes it with a two-toothed rake ; in this way the fine tin-stone settles down 



